Further Evidence That Route of Estrogen Administration Affects VTE Risk

Use of oral estrogen by menopausal women raises risk for venous thromboembolism (VTE), and data suggest that risk is lower with transdermal preparations. To address this distinction in a real-world, commercially insured, North American population, investigators conducted a retrospective matched cohort study using health insurance claims data in new users (age, ≥35) of a transdermal estradiol system or oral estrogen therapy. A total of 27,018 transdermal users were matched with an equal number of oral estrogen users; the study was funded by the manufacturer of a transdermal system.

VTE developed in 115 transdermal estradiol users and in 164 oral estrogen users. Adjusted analysis showed that transdermal estradiol users had significantly lower …